Refrigeration



I 30,;19372 H. B. LAWTON 2,075,349

REFRIGERATION Filed Aug. 26, 1935,

Pump a? by ('OMMIJSM INVENTOR.

H4? VEYB. LA'WTO/V BY 411 M MR A TTOIUVEY.

Patented Mar. 30, 1937 UNITED STATES REFRIGERATION Harvey B. Lawton,

Bloomington, 111., assignor to Williams Oil-O-Matic Heating Corporation, Bloomington, 111., a. corporation of Illinois Application August 26, 1935, Serial No. 37,911

5 Claims.

This invention relates to improvements in refrigeration and more particularly to electrically controlled and operated refrigeration apparatus.

In both the compression and absorption type of electrically controlled and operated refrigeration apparatus, the refrigerant is allowed to change from the liquid to the gaseous state in a cooling coil or evaporator, and in so doing, absorbs heat from the surrounding atmosphere. The gaseous refrigerant is returned from the cooling coil or evaporator to either the compressor or absorber, as the case may be, by the suction due to the reduced pressure in the respective elements. The operation of the apparatus causes the circulation of the refrigerant through the cooling coil or evaporator and the admission of the liquid refrigerant to the cooling coil or evaporator is automatically controlled by an expansion valve or by a float-operated valve in accordance with the system employed.

It is an object of this invention to automatically control theoperation of the apparatus so that when the circulation of the refrigerant ceases as the apparatus becomes idle, it will create and maintain a, pressure below atmospheric pressures or vacuum within the return pipe of the gaseous refrigerant from the cooling coil or evaporator, and, therefore, make it impossible for any of the gaseous refrigerant to leak into the atmosphere to cause a fire or health hazard.

With the above and other objects in view, reference is made to the figure upon the accompanying drawing, which illustrates, partly in elevation and partly in diagram, a preferred embodiment of this invention with the understanding that minor detail changes may be made without departing from the scope thereof.

In the embodiment illustrated, a motor M is shown diagrammatically in connection with a wiring diagram in' which wires I and 2 lead from the motor M through a hand switch S to a commercial source of electricity. If the apparatus is automatically controlled, a relay would be substituted for hand switch S. If the invention is applied to a compression type refrigerating apparatus, the motor M will operate the compressor, and if an absorption type of apparatus, the motor M will operate a circulating pump for the solution, so, in either case, the energizing of the motor will initiate operation. The refrigerant in both cases is lead by a pipe 3 to a commercial cooling coil CC entering the upper coils from a manifold 4 and is discharged from the lower coils into a manifold 5 and from thence I switch I3 is connected by into a pipe 6, which will return the refrigerant to the apparatus.

The cooling coil CC is shown as preferably controlled by a commercial thermostatically operated expansion valve 1 in the pipe 3 having a thermal actuator 8 mounted in the lower manifold 5 whereby the expansion valve automatically admits sufiicient refrigerant to maintain a predetermined temperature within the cooling coil. A commercial solenoid valve 9 is interposed in pipe 3 between the expansion valve 1 and source of liquid refrigerant and is connected by wire I!) to commercial wire I and by wire it through a commercial pressure switch H to commercial line 2. The pressure switch 12 is arranged and so connected to pipe 6 to be actuated by the pressure therein. Another commercial pressure wires l4 and I5 to the commercial line I beyond the hand switch S and to the line lead of the motor M, also connected to line I, respectively, and is so arranged and connected to pipe 6 to be actuated by the pressure therein. A wire l6 connects the other line of the motor M and wire II to the commercial line 2 beyond the hand switch S.

The solenoid valve 9 is of commercial construction which is normally closed and opens when the circuit is established through it. The pressure switches l2 and I3 are likewise of commercial construction and are adjustable, such as disclosed in Patent 1,791,839, of February 10, 1931. In this use, the switch I3 is adjusted to close at one inch vacuum and to open at approximately five and a half inches of vacuum, while switch I! is adjusted to open at two inches of vacuum and to close at approximately ten inches of vacuum.

In describing the operation of this invention, it is necessary to refer to a concrete example or refrigerating apparatus, and as this invention has been operated in connection with a commercial absorption type of refrigerating apparatus such as described in Serial No. 736,232, filed July 20, 1934, which is particularly adapted to employ dichloromonofluoromethane as the refrigerant and ethyl ether of diethylene glycol acetate as the solvent, the conditions existing in such an apparatus will be used.

Assuming the apparatus has been idle with the switch S open, such as during a period between normal operations, and assuming approximately four inches of vacuum in the return pipe 6, switch l2 will be open breaking the circuit through the solenoid valve 9 so the valve will be closed in pipe 3, and switch It will be open.

Upon closing switch 8 to produce refrigeration, the motor M will start to operate, causing the vacuum in pipe 6 to increase until it reaches approximately ten inches, and switch i2 will close 5 to energize the solenoid 9, and the valve in pipe 3 will open and admit the refrigerant to enter the cooling coil CC to produce refrigeration, and under normal running conditions the vacuum will becometabout fourinches pipe 6. W aten-a t e s i duced, switch S is opened, the mo or M ceases operation, and the vacuum in pipe 8 decreases until it reaches two inches and then switch I! opens. The solenoid valve 9 in pipe 3 closes the 15 admission of refrigerant into the co ling coil CC when the motor ceases to in pipe 6 will continue to cc 1 reaches one inch, switch l3 c1 from commercial line I throughwiresx liQIlflQif 2'0 tor M, and wire l6, so that the motor ltgw be gin tq. perate, The circuit through switch l2" b'iiidpn, the siil'rrii'd valve a inpipeslj is closed;

d as no refrigerant can enterlthe 'coolingscoil; o rases hewacuum circuit and operating to open when the motor circuit is closed, a pressure actuated switch in the solenoid circuit connected to the return conduit from the coil adjusted to open at a pressure slightly less than atmospheric pressure and to close at a pressure considerably less, whereby upon closing the motor circuit the solenoid valve is notj' opened -until theroperalgioq f the motor has "createda pressure life ireiturn conduit con 'derably less than atmospheric pressure.

The structure of claim 2, wherein an additional c ircuit is provided from the source to inc iidthe motoradapted to operate the motor whemtheamotor switch is open, including an additio pressur actuated switch connected to the return conduit idjusted to close said circuit tooperate the motor independently of the solenoid vaiveto 'r'ri'airitain a predetermined less than atmospheric pressure in the return conduit durins the-neriadslstfiiif g the rie rhea-ap a a us 9 (1,116

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